diff mbox

x86-64: Check FMA_Usable in ifunc-mathvec-avx2.h [BZ #21966]

Message ID 20170817230044.GA22607@gmail.com
State New
Headers show

Commit Message

H.J. Lu Aug. 17, 2017, 11 p.m. UTC 
Since the AVX2 version of mathvec functions uses FMA, it can only be
used when FMA is usable.

Any comments?

Andrew, please take a look and check if it should be fixed on branches.

Thanks.

H.J.
	[BZ #21966]
	* sysdeps/x86_64/fpu/multiarch/ifunc-mathvec-avx2.h
	(IFUNC_SELECTOR): Don't use the AVX2 version if FMA isn't
	usable.
---
 sysdeps/x86_64/fpu/multiarch/ifunc-mathvec-avx2.h | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

Comments

Senkevich, Andrew Aug. 18, 2017, 1:02 p.m. UTC | #1 
> -----Original Message-----
> From: Lu, Hongjiu
> Sent: Friday, August 18, 2017 01:01
> To: GNU C Library <libc-alpha@sourceware.org>
> Cc: Senkevich, Andrew <andrew.senkevich@intel.com>
> Subject: [PATCH] x86-64: Check FMA_Usable in ifunc-mathvec-avx2.h [BZ
> #21966]
> 
> Since the AVX2 version of mathvec functions uses FMA, it can only be used when
> FMA is usable.
> 
> Any comments?
> 
> Andrew, please take a look and check if it should be fixed on branches.

Yes, branches should be fixed also. Thanks.


--
Andrew
H.J. Lu Aug. 18, 2017, 1:21 p.m. UTC | #2 
On Fri, Aug 18, 2017 at 6:02 AM, Senkevich, Andrew
<andrew.senkevich@intel.com> wrote:
>> -----Original Message-----
>> From: Lu, Hongjiu
>> Sent: Friday, August 18, 2017 01:01
>> To: GNU C Library <libc-alpha@sourceware.org>
>> Cc: Senkevich, Andrew <andrew.senkevich@intel.com>
>> Subject: [PATCH] x86-64: Check FMA_Usable in ifunc-mathvec-avx2.h [BZ
>> #21966]
>>
>> Since the AVX2 version of mathvec functions uses FMA, it can only be used when
>> FMA is usable.
>>
>> Any comments?
>>
>> Andrew, please take a look and check if it should be fixed on branches.
>
> Yes, branches should be fixed also. Thanks.
>

Hi Andrew,

I checked my patch into master branch.  Can you take care of
branches?

Thanks.
diff mbox

Patch

diff --git a/sysdeps/x86_64/fpu/multiarch/ifunc-mathvec-avx2.h b/sysdeps/x86_64/fpu/multiarch/ifunc-mathvec-avx2.h
index a43d4c54fa..ccda2748c5 100644
--- a/sysdeps/x86_64/fpu/multiarch/ifunc-mathvec-avx2.h
+++ b/sysdeps/x86_64/fpu/multiarch/ifunc-mathvec-avx2.h
@@ -31,7 +31,8 @@  IFUNC_SELECTOR (void)
 {
   const struct cpu_features* cpu_features = __get_cpu_features ();
 
-  if (CPU_FEATURES_ARCH_P (cpu_features, AVX2_Usable))
+  if (CPU_FEATURES_ARCH_P (cpu_features, FMA_Usable)
+      && CPU_FEATURES_ARCH_P (cpu_features, AVX2_Usable))
     return OPTIMIZE (avx2);
 
   return OPTIMIZE (sse_wrapper);